C++ program code:

//Header file section
#include <iostream>
#include <vector>
using namespace std;

//Define constant variable names
const int ROWS = 7;
const int COLS = 4;

// Function to display the seat pattern
void displaySeats(const vector<vector<char>>& seats) 
{
    for (int i = 0; i < ROWS; i++)
    {
        for (int j = 0; j < COLS; j++)
        {
            cout << seats[i][j] << ' ';
        }
        cout << endl;
    }
}

// Function to check if a seat is available
bool isSeatAvailable(const vector<vector<char>>& seats, int row, int col) 
{
    return seats[row][col] != 'X';
}

// Function to assign a seat
void assignSeat(vector<vector<char>>& seats, int row, int col)
{
    seats[row][col] = 'X';
}
//Program starts with a main function
int main()
{
    // Create and initialize the seat pattern
    vector<vector<char>> seats(ROWS, vector<char>(COLS, ' '));

    // Display the initial seat pattern
    displaySeats(seats);

    // Main loop to assign seats
    while (true) 
    {
        int row, col;

        // Prompt for seat choice
        cout << "Enter the row and column of the seat (e.g., 1 2): ";
        cin >> row >> col;

        // Adjust row and col for 0-based indexing
        row--;
        col--;

        // Check if the seat is valid
        if (row < 0 || row >= ROWS || col < 0 || col >= COLS) {
            cout << "Invalid seat choice. Please try again." << endl;
            continue;
        }

        // Check if the seat is available
        if (isSeatAvailable(seats, row, col)) 
        {
            // Assign the seat
            assignSeat(seats, row, col);
            cout << "Seat assigned successfully!" << endl;

            // Display the updated seat pattern
            displaySeats(seats);
        } else 
        {
            cout << "Sorry, that seat is already occupied. Please choose another seat." << endl;
        }

        // Check if all seats are filled
        bool allSeatsFilled = true;
        for (int i = 0; i < ROWS; i++) {
            for (int j = 0; j < COLS; j++) 
            {
                if (seats[i][j] != 'X') 
                {
                    allSeatsFilled = false;
                    break;
                }
            }
            if (!allSeatsFilled) 
            {
                break;
            }
        }

        // Break the loop if all seats are filled or user signals to end
        if (allSeatsFilled) 
        {
            cout << "All seats are filled. Exiting the program." << endl;
            break;
        }

        char choice;
        cout << "Do you want to continue assigning seats? (Y/N): ";
        cin >> choice;

        // Break the loop if the user chooses to end
        if (choice == 'N' || choice == 'n') 
        {
            cout << "Exiting the program." << endl;
            break;
        }
    }

    return 0;
}

OUTPUT OF THE PROGRAM CODE:

1 A B C D
2 A B C D
3 A B C D
4 A B C D
5 A B C D
6 A B C D
7 A B C D

Enter the row and column of the seat (e.g., 1 2): 1 1
Seat assigned successfully!
X B C D
2 A B C D
3 A B C D
4 A B C D
5 A B C D
6 A B C D
7 A B C D

Do you want to continue assigning seats? (Y/N): Y
Enter the row and column of the seat (e.g., 1 2): 2 2
Seat assigned successfully!
X B C D
2 A X C D
3 A B C D
4 A B C D
5 A B C D
6 A B C D
7 A B C D

Do you want to continue assigning seats? (Y/N): Y
Enter the row and column of the seat (e.g., 1 2): 4 3
Seat assigned successfully!
X B C D
2 A X C D
3 A B C D
4 A B X D
5 A B C D
6 A B C D
7 A B C D

Do you want to continue assigning seats? (Y/N): N
Exiting the program.